overloaded alternative of varargs method invoke-blocks intended target if Nothing is inferred

[scabug]

scala> def f(xs: List[Int], ys: AnyRef*) = () ; def f(xs: AnyRef*) = ()
f: (xs: List[Int], ys: AnyRef*)Unit <and> (xs: AnyRef*)Unit
f: (xs: List[Int], ys: AnyRef*)Unit <and> (xs: AnyRef*)Unit

scala> f()

scala> f(Nil: _*)
<console>:9: error: no `: _*' annotation allowed here
(such annotations are only allowed in arguments to *-parameters)
              f(Nil: _*)
                   ^

scala> f((Nil: List[String]): _*)

scala> f(Array(): _*)
<console>:9: error: no `: _*' annotation allowed here
(such annotations are only allowed in arguments to *-parameters)
              f(Array(): _*)
                       ^

scala> f(Array[String](): _*)

[scabug]

Imported From: https://issues.scala-lang.org/browse/SI-5859?orig=1
Reporter: @paulp

[scabug]

@adriaanm said:
the Array(): _* invocation should be accepted

[scabug]

@paulp said:
(As well as the Nil: _* invocation.)

[scabug]

@retronym said:
I'm working on a fix here: https://github.com/retronym/scala/compare/ticket/5989-2

[scabug]

@paulp said:
Sorry for not marking it in the ticket, but I fixed this a few days ago.

scala/scala@8886d22cd6

I sort of marked it when I took ownership of it, which usually means I've fixed it locally.

[scabug]

@retronym said:
No worries. I don't have a motivating test case for it, but I'm pretty sure isVarArgsOnly should be propagated here: https://github.com/scala/scala/blob/8886d2/src/compiler/scala/tools/nsc/typechecker/Infer.scala#L1651

[scabug]

@paulp said:
This must be why I say "Boolean parameters are bad; Booleans with defaults are worse." That kind of error is pretty much assured by the method signature. Additional pull request encouraged.

[scabug]

@retronym said:
More generally, recursive methods with defaults are open to this error. I've seen it often enough that I might add a check to Xlint ("recursive call should not use defaults").

[scabug]

@paulp said:
If you do, it will LGTM.

[scabug]

@retronym said:
It's a tad noisy:

retronym/scala@3bfb6830#commitcomment-1949765

[scabug]

@adriaanm said:
reopening for 2.10.1-RC1 backport